Scientists at the Nisia Floresta Common Marmoset Research Station in Natal, Brazil, have been studying the ecology and behavior of common marmosets (Callithrix jacchus) since 1991. Now, they are collaborating with our Center to learn more. Maria Bernardete Sousa, Ph.D., has been working with Toni Ziegler in our Physiological Ethology Research Group since last August. Ziegler, also an associate scientist in the UW-Madison Department of Psychology, is working with Sousa on fecal hormonal analysis in marmosets.
"We are seeking more information about fecal steroid excretion in these species," says Ziegler. Adds Sousa, "Studying levels of hormones such as progesterone and cortisol can give us the information we need to monitor the reproductive conditions of females in the wild and also learn how varying degrees of social stress within the animals' natural groups affect their reproductive cycles." "Although marmosets are one of the most studied species in captivity," Sousa says, "we need to clarify important aspects of their mating strategies and reproductive systems." This better understanding could help scientists further conservation efforts for New World Primates in the wild.
Ziegler recently published a study on techniques for measuring both circulating and excreted hormones to demonstrate their relationship to the circulating luteinizing hormone (LH). She explains that the techniques will allow researchers to consistently determine the relationship between the preovulatory LH peak and the onset of fecal steroid increase. "These techniques will give us the means to monitor ovarian function in wild marmosets and tamarins," she says.
This April, Sousa returns to Brazil to share what she has learned with researchers at the Nisia Floresta field station and the Universidade Federal do Rio Grande do Norte in Natal.
"At the field station, we study about six groups of between 6 and 15 animals living in natural conditions and about 100 marmosets living in outdoor cages," she describes. Scientists at the University work in three lines of research: chronobiology, the study of biological clocks in marmosets; ecology and social organization; and reproductive and sexual behavior, Sousa's focus.
The field station is 45 km from Natal, the capital of the state of Rio Grande do Norte. A description of the climate, vegetation and the marmoset groups and scientific activities involving them appears in Neotropical Primates (Vol. 2, Number 4, December 1994).
Sousa stresses the importance of such collaborations as scientists are seeking more knowledge about primate species in the wild. "Brazil has the largest number of New World Primates and new species are still being discovered." She referred to one of the more recent articles on the subject that appeared in a somewhat unexpected place, the Feb. 3 issue of Sports Illustrated (the Green Bay Packers Superbowl issue). The article, "You Looking For Me?" described a new species of marmoset recently discovered in Amazonia. The animal's habitat is tucked into the fork of the Rio Madeira and Rio Aripuana in northwestern Brazil.
Copyright 1997. Wisconsin Regional Primate Research Center.